PHYTOREMEDIATION OF CADMIUM POLLUTANTS IN WASTEWATER BY USING CERATOPHYLLUM DEMERSUM L. AS AN AQUATIC MACROPHYTES

Abstract

The current study carried out a test of phytoremediation for the removal of cadmium Cd pollutants, which is one of the most important heavy metal pollutants in the aquatic environment, by using the submerged Ceratophyllum demersum L., as one of the aquatic macrophytes which is commonly named coon tail or rigid hornwort, and evaluating its effectiveness in phytoremediation of cadmium Cd pollutants from different sources of wastewater under the current study which includes Cooling Electric Generators (CEG), Domestic Sewage Water (DSW), and Washing and Lubricating Cars (WLC). 15 random water samples were collected during February and March of 2021, with 3 replicates for each sample. C. demersum (9) plant samples were also randomly collected in 2021, with three replications. A sampling of plants included withdrawing the entire plant (roots-like, stems-like and leaves-like branchlets) with an amount of river water. It was found from the current study that the best values for Cd removal were observed during the fifteenth and twelfth days of the aquaculture durations which were represented by the lowest values of Cd concentrations as 7.9 ± 4.3 μg/L and 31.5±20.2 μg/L respectively, while the worst values for Cd removal were showed during the third and sixth days of the aquaculture durations which represented by the highest values of Cd concentrations as 86.9±40.8 μg/L and 38.6±19 μg/L respectively. The best significant abilities of C. demersum L.to reduce Cd levels were in aquaculture treated with (CEG) wastewater as about 97.9%, 94.1%, and 91.3 % during 15, 12, and 9 respectively days of aquaculture durations followed by removal percentages in aquaculture treated with (DSW) as 92% and 89.0% during 15 and 6 respectively days of aquaculture durations and (WLC) wastewater, as 85.3% in the fifteenth day of aquaculture durations. These results mean that C. demersum probably has contributed to high phytoremoval rates for Cd pollutants from its in vitro polluted aquaculture, especially in the late durations of aquaculture durations. It was also found that the highest accumulation levels for Cd were in the tissues of leaves-like, which were about 189.9±74.7 μg/g, followed by tissues of roots-like, as about 133.2±65.4 μg/g, while the lowest values were in the tissues of stems-like, as about 72.9±28.8 μg/g. The best significant cumulative adsorption percentage values for Cd in leaves-like tissues of C. demersum L. were ascending as about 81.1%, 80.3%, 78.7%, and 75.9% during 15, 12, 9, and 6 respectively days of aquaculture durations followed by percentage values for Cd adsorption percentage in roots-like as 74.7% and 73.5 % during 15 and 12 respectively days of aquaculture durations. The less significant cumulative adsorption percentage value for Cd in stems-like tissues of C. demersum L. was 11.8% followed by 32.5% in roots-like during the third day of the aquaculture duration. These results mean that cumulative tissue adsorption for Cd particularly tends to concentrate progressively more in leaves-like tissues than in the roots-like of C. demersum, and tends to be less concentrated in the stem-like internodes of these submerged aquatic plants.